1. Field of the Invention
The invention relates to a water-proof connector, and more particularly to a water-proof modular connector.
2. Description of the Related Art
A connector through which communication cables are connected to each other is necessary to be water-proofed, because a communication unit including the connector, such as a radio-signal base station in a mobile communication system, is often placed outside. A variety of water-proof connectors has been suggested.
For instance, Japanese Patent Application Publication No. 2001-237023 has suggested a coaxial connector having a water-proof structure in which a cylindrical packing is compressed onto an inner wall of a seat by means of a nut.
Japanese Patent Application Publication No. 2001-6798 has suggested a water-proof connector including a male connector housing having a hood, and a female connector housing having an outer piece and an inner piece. The male and female connector housings are hermetically coupled to each other through a water-proof ring assembly to ensure that a room in which a metal terminal is arranged is water-proofed.
Japanese Patent Application Publication No. 9-129322 has suggested a water-proof coaxial connector obtained by adding an O-ring and a water-proof ring to a non-water-proof coaxial connector.
Japanese Patent Application Publication No. 8-155025 has suggested a connector used for medical application, including a pair of connectors one of which has a female thread portion formed in an inner surface, and the other of which a male thread portion to be threaded into the female thread portion.
Japanese Patent Application Publication No. 2002-289292 has suggested a water-proof connector including a water-proof cap in a chamber formed in a connector housing. When the connector housing is engaged to a rear holder, water-proof condition is ensured between a cable and the connector housing. The water-proof cap has a cylindrical seal, a skirt-shaped seal, and a hole through which a cable passes. The connector housing has a recess in which the skirt-shaped seal is accommodated. The rear holder has a cylinder comprised of a first portion which ensures water-proof condition by making close contact with a lip formed on an outer surface of the cylindrical seal, and a second portion which ensures water-proof condition by compressing the skirt-shaped seal onto an inner wall of the recess.
Japanese Patent Application Publication No. 2002-184516 has suggested a water-proof connector through which a connector housing having a rear surface onto which grommet is formed is fit to a second housing such that a bolt passing through the grommet couples the housings to each other. The grommet is formed with a seal making contact with a shank of the bolt. The connector housing has a portion which cooperates with a head of the bolt to sandwich the grommet therebetween. The portion is formed with a recess to which at least a part of the seal can be fit.
Japanese Patent Application Publication No. 2002-313114 has suggested a water-proof connector including a pair of connector housings having cylindrical portions to be fit into each other. A water-proof ring is sandwiched between the cylindrical portions. Each of the connector housings is formed with a pin to be fit into a hole formed in the water-proof ring.
However, these conventional water-proof connectors can be applied to a coaxial connector or a pin connector, but cannot be applied to a modular connector. In a communication cable used in a radio-signal base station usually placed outside, non-water-proof modular connectors are used. Accordingly, it is necessary to surely connect communication cables each including a modular connector, to each other outside for enhancement of safety. In addition, a modular connector is necessary to be water-proofed in order to withstand outside use.